The popular image of the mountain climber is of a person carefully climbing a steep cliff with a network of safety ropes, but it is not the only kind. Many climbers now enjoy bouldering. It’s more accessible and better for the environment.

Here is an example of a climber addressing a bouldering problem.

Figure 1: The climber has two routes she could take, one to the left and one to the right. The left one appears easier because it has a jug within easy reach, but look what happens if she chooses that direction. She gets stuck on the rock and has to go back down. Sometimes that is even more difficult than going up.

Figure 2: The climber takes the one to the right this time. Using a foothold and placing her righ hand in a crimp, she is able to lift herself up and locate other handholds. After only a few moves, she is able to throw her leg over the top of the boulder and pull herself up.

I have learned something about myself since I moved from Long Island to Florida three years ago. Even though I own a home in Port St. Lucie just minutes from the ocean, an uncontrollable urge wells up to return to Long Island even as others make their way south. I guess I am a snowbird stuck in reverse. Instead of enjoying Florida’s mild winters, I willingly endure the severe weather on Long Island, the place I called home for 65 years.

I’m like a migratory bird that has lost its sense of timing and direction, my wings flapping against season.

So what makes me fly against the tide of snowbirds? The answer has a lot to do with my reluctance to give up the things that define who I am. Once I hear that the temperature on Long Island has dipped into the range of 40 to 50 degrees, I begin to long for the sight and crackling sound of a wood fire. I also long for the bright display o£ colors — first in the £all trees, and then in the limits around homes and at Rockefeller Center. Floridians decorate too, but can’t create the special feel of a New England winter.

I suppose the biggest reason why I telum is to celebrate the holidays with people I haven’t seen in months. What could be better than sitting with family and friends for a Thanksgiving turkey din ner, or watching neighbors’ children excitedly open gifts on Christmas? Even the first snowfall seems special. I especially enjoy seeing a bright red bird settling on a snow-covered branch ( My wife and I spend winters at a retirement community in Ridge, and I’m grateful that I don’t have to shovel.）

While these simple pleasures are not unique to Long Island, they are some of the reasmis why I come back. Who says you can’t go home?

It’s undeniable that spending time outdoors and in nature lifts our spirits and makes us feel more centered and at peace. When we breathe in fresh air, and enjoy the beauty of trees, streams and oceans, we naturally tend to feel more connected to ourselves and others.

Over the past decade, scientists have been exploring why nature — and dirt specifically — is such a powerful tool in improving our mood. According to researchers, the secret may lie in the mi¬crobes （微生物）of the soil. One bacterium specifically----Mycobacterium Vaccae （M. Vaccae） —has been identified as having the power to affect our moods and cognitive function as well.

Experiments conducted at Sage Colleges in New York found that contact with M. Vaccae can increase serotonin levels in the brain — a chemical that is associated with higher levels of happi¬ness ,increased focus, and reduced anxiety. In order to explore how the bacteria can improve learn¬ing, researchers Dory Mathews and Susan Jenks experimented with mice in a maze. Mice that in¬gested the bacteria navigated the maze twice as fast as the control group and proved less anxious as well.

Humans can absorb M. Vaccae just by playing in the dirt. We take in it when we breathe, we consume it in organic vegetables, and it can also enter our bloodstream through skin contact, espe¬cially where we have open cuts. This may explain why children in school perform better after break.

Neuroscientist Christopher Lowry at the University of Bristol in England believes that he has i- dentified why this incredible bacterium works. "What we think happens is that the bacteria activate immune cells, which release chemicals called cytokines that then act on receptors on the sensory nerves to increase their activity. ”

Beyond the power of M. Vaceae, scientists have been proving for decades that exposure to dirt, and the huge number of microbes found in dirt, can strengthen our immune system. When our body comes into contact with bacteria, it stores die infonnation in a type of library and can then use that information to fight sickness and infection more effectively.

Happiness, focus, less anxiety......I’ll   take a double dose of dirt; please!

It is becoming increasingly important for researchers to closely monitor our ocean life. However, observing sea creatures Up close is almost impossible since human presence scares them. Now, thanks to The Soft Robotic Fish, also known as SoFi, researchers may be able to keep a close eye on the sea creatures.

Built by MIT Computer Science and Artificial Intelligence Laboratory ( CSAIL), the white re- mote-controlled robot resembles the real fish, complete with a tail that waves from side to side. Though not the first autonomous underwater vehicle (AUV) created to monitor the ocean , SoFi set- tles many of the problems that have blocked the usefulness of the previous robot fish.

Previous AUVs have had to be linked to boats because radio frequency communications don’t work well underwater. To overcome the problem, Director of die CSALL Daniela Rus and her team used sound waves. The technology can travel greater distances allowing divers to pilot SoFi from up to 50 feet away.

Also limiting the usefulness of traditional AUVs is the risk of collision. With the outside made of soft silicone （硅树脂）rubber and flexible plastic that keeps its inbuilt electronics dry, SoFi po¬ses no such danger. " Collision avoidance often leads to unnecessary movement, since the robot has to settle for a collision-free path" , says Rus. "In contrast, a soft robot is not only more likely to survive a collision but also could use it as information to form a more workable movement plan next time around. "

During test dives, SoFi moved alongside the ocean life at depths of 50 feet for up to 40 minutes at a time, taking photos and making videos. The researchers say sometimes the fish would swim a- longside the strange-looking robot-fish out of curiosity, while at other times they took no notice of its existence.

While SoFi presently only records video, future versions will include sensors. The researchers also hope to make it more autonomous. "We imagine someday it might help us uncover more secrets from the amazing underwater world that we know so little about," says Rus.